Tick lag for your understanding is what we see as, mobs exhibiting "low gravity" characteristics
moving slow and falling slow, this also affects how fast minecarts move, my experience makes minecarts slower than running, this also makes horses move slower while riding them, dropped items vibrate in the air and drop slowly, and effects such as poison, burning, and wither also do damage slower than normal, you may refer to this as something else, but the folks in the community best know this as "Tick lag" in reference to redstone ticks, before the recebt patchs i never had such issue in worlds, but as of now, its a problem, and this tick lag could be the cause of the freezing and crashing on the switch edition that i talked about on another issue report. I would really lime to see this issue properly fixed in the next patch to make the game run as it should.